All the genuine ones I've seen are a bowl, with lamellar or textile defences hanging from it. The ones like this, with solid back and sides extended well below the front (or you could say that the front is cut-out for the eyes) have been fake. So I'd assume the left-hand (Tibetan) one to be fake.

The Bhutanese helmet looks genuine, as far as I can tell from the photo. Plausibly 19th century. The bowl could be older, with newer cloth.